Typically, I count on having to replace the roof and windows on every property.

Looking to replace all the carpet downstairs and the cheap vinyl sheet flooring.

In my area it is $6 sf to replace. 1600 sf*$6=$9600/10 year life span/12 months in a year=$80 per month for 1 item. i use a minimum of 10% for capex.

There's multiple components of this business, and successful investors don't try to do everything themselves.

Is replacement plumbing now going away from copper to PEX?

Had it been a repair / replacement the permit would still need to be pulled, but it would likely have no significant impact on your taxes.Adding bathrooms, bedrooms, etc. impacts the value of the property (usually value goes up by adding these things), and towns know that, so they want to make sure they are taxing you at the appropriate value.

., depending on your lifestyle, 65% income replacement is generally low.  

If the owner does not, then just buy a spare of each size and replace them as needed.If you are having one that goes out all the time, you may have an electrical problem, and FOR YOUR OWN SAFETY tell the owner about it NOW (so you don't burn to death in an electrical fire).Good Luck! 

Then are they going to charge you another placement fee for the replacement tenant.  

Do they flag stuff like a furnace or water heater that was replaced and didn't pull permit or are they usually pretty relax unless theres a tenant complaint?